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混合制冷剂冰箱对比试验研究 总被引:2,自引:0,他引:2
本文对二元混合工质HFC152a/HCFC22、 HFC152a/HFC125在冰箱上应用的制冷循环性能进行了详细的理论计算和分析,并且对这两种混合工质灌注式替代CFC12、在最佳配比和充灌量下的冰箱主要制冷性能进行了对比试验研究。试验结果表明:在合适的配比和充灌量下混合工质冰箱制冷性能指标满足国家标准要求, HFC152a/HFC125在最佳充灌量为97 g时,试验冰箱耗电量为1.156 kW·h/24h,比CFC12节能10%,比HFC152a/HCFC22节能0.81%。因此, HFC1S2a/HFC125比HFC152a/HCFC22更适合于灌注式替代CFC12。 相似文献
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本文对R134a、R290、R600a及R600等四种制冷剂用于双回路耦合制冷系统的性能进行模拟计算。其中R600的当量性能系数最高、单位质量制冷量最大而容积制冷量最小;R600a排气温度最低;R290循环压比最小。对由R290、R600及R600a组成的不同混合制冷剂进行模拟计算,当小端温差一定时,混合制冷剂当量性能系数高于纯质;当有效换热温差一定时,混合制冷剂R290/R600a当量性能系数与纯质R600相当,循环压比稍高于R290,最高排气温度低于所选纯质制冷剂. 相似文献
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新型氟代三苯胺衍生物的合成和光谱特性研究 总被引:1,自引:0,他引:1
设计和合成了一种新型氟代三苯胺衍生物——N,N,N′,N′-四苯基-[2′,2″,3′,3″,5′,5″,6′,6″-八氟对四联苯]-4,4″′-二胺(OFTPA)。通过元素分析、熔点测定、红外光谱和1 H NMR谱等手段对OFTPA的分子结构进行了表征,并对其主要的红外光谱吸收峰和1 H NMR谱带进行了归属分析。利用紫外-可见吸收光谱、荧光光谱和循环伏安法(CV)对OFTPA的电子能级结构和发光性能进行了研究。紫外-可见吸收光谱测定结果表明,OFTPA薄膜的最大吸收峰波长为355nm,光学带隙(Eg)为3.09eV。荧光光谱测定结果表明,OFTPA薄膜在365nm紫外光的激发下,产生发光峰波长在448nm附近、半峰宽(FWHM)为68nm的蓝光发射,色纯度高,有望成为优良的蓝光发射材料。循环伏安法测定结果表明,OFTPA的最高占有轨道(HOMO)能级为-5.41eV,最低空轨道(LUMO)能级为-2.32eV,具有良好的空穴传输性能。研究结果为进一步研究其在有机光电器件中的应用提供了参考。 相似文献
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采用旋涂法制备了厚度为140 nm的聚(偏氟乙烯-三氟乙烯)[P(VDF-TrFE)]纳米薄膜, 研究了不同退火温度以及环境相对湿度对薄膜的极化反转和疲劳性能的影响. 运用X射线衍射仪、扫描电子显微镜和傅里叶变换红外光谱仪等测试技术对薄膜的微结构进行了表征. 实验结果表明, 通过不同温度的退火处理, P(VDF-TrFE)铁电薄膜的结晶度随着退火温度的升高而不断提高, 并且一定的温度范围内的退火处理可以提高薄膜的极化性能; 此外, P(VDF-TrFE) 铁电薄膜性能还表现出一定的环境湿度的敏感特性, 这与薄膜的物理性能和结构特点密切相关; P(VDF-TrFE)铁电薄膜在不同的环境湿度条件下 表现出较好的电学特性, 其漏电流均保持在10 -7A/cm2 的较低水平. 本工作揭示了再退火过程对薄膜的极化反转速度和疲劳恢复特性的影响, 并结合薄膜二次疲劳结果, 探讨了薄膜可逆的内部疲劳恢复特性机理. 相似文献
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三氟碘甲烷的新气相状态方程和输运物性 总被引:2,自引:0,他引:2
提出了三氟碘甲烷(CF3I)的新蒸气压方程和新状态方程;给出了CF3I的偏心因子、正常沸点等物性参数,并与文献值进行了比较.使用毛细管粘度计测量了CF3I的253~338K的饱和液粘度,采用以钽丝为热线的双线瞬态热线法测量了CF3I的气相导热系数,并分别给出了关联式. 相似文献
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2-三氟甲基吡啶的合成与光谱表征 总被引:1,自引:0,他引:1
以2-氯基吡啶为原料,合成2-溴吡啶(收率68%)和2-碘吡啶(收率56%);2-溴吡啶和2-碘吡啶与三氟乙酸钾反应,得2-三氟甲基吡啶(收率56%-72%).通过NMR和元素分析对产物的结构进行了表征.该合成路线的优点是原料易得,反应条件温和,收率较高,总收率为38%-42%. 相似文献
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研究了利用弛豫型铁电三元聚合物薄膜P(VDF-TrFE-CFE)的热释电性质,以温度波动作为初始能量形式进行热电能量的采集。由于该聚合物薄膜在发生由温度变化诱导的纳米极性区极化机制转换时,介电常数表现出明显的非线性变化,所以可以结合Ericsson循环实现热电能量采集。实验结果显示,最佳能量采集温度区间为20~-20℃,利用不同温度下的单极性电滞回线进行Ericsson循环模拟,两种模拟方式分别实现能量采集最大值和最小值,并从微观角度给出了两种模式的解释。同时研究了温度波动和外加电场对能量采集的影响。在外加电场100 kV·mm-1、温度波动为40℃的情况下,能量采集值达到3483 mJ·cm-3。与单晶材料相比,能量采集值提高了10倍。当工作温度降低至室温时,材料具有柔性,在能量采集方面具有应用潜力。 相似文献
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本文报告了用多种核磁共振实验方法并结合其它结构信息,研究并首次确定了内蒙产的乌拉尔甘草(Glycyrrhiza uralensis Fisch)中一种新甘草三萜内酯的化学结构并命名为甘乌内酯(Glyuranolide)。 相似文献
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《Journal of Macromolecular Science: Physics》2013,52(5):639-667
Isotactic poly(3-hydroxybutyrate) (P3HB) is an aliphatic polyester obtained by bacterial fermentation. This truly biodegradable polymer has been widely investigated, mainly with the aim to replace conventional plastics, which cause environmental pollution. To improve its properties, extensive studies have been conducted to modify it properly by copolymerization or blending with other polymers. Macroscopic properties of polymers, particularly of polymer blends, are strongly affected by their microstructure, especially by the allocation of different phases and their level of dispersion and adhesion. In nonreactive blends, the adhesion level is mainly determined by the similarity between the chemical structure of the components, and the arrangement of the phases is remarkably controlled by the crystallization conditions. The superstructure of the crystalline phases accounts for the mechanical resistance of the blend, but the composition and the distribution of the amorphous phases also play an important role, especially with respect to toughness properties. This article reviews data on thermal properties and the crystallization process of P3HB and its copolymers, both alone and in the presence of other polymers. In particular, copolymers of 3-hydroxybutyrate with 3-hydroxyvalerate and with 4-hydroxybutyrate and blends of P3HB and the copolymers with atactic poly(3-hydroxybutyrate), poly(vinyl acetate), poly(vinyl alcohol), poly(ethylene oxide), poly(methylene oxide), poly(epichlorohydrin), and poly(methyl methacrylate) are considered. Major attention is directed toward the influence of miscibility and composition on solidification kinetics and crystal structure with the objective to provide an overview of the current state of the art. 相似文献
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The present review emphasizes the role of hydrodynamic cavitation (HC) and acoustic cavitation in clean and green technologies for selected fuels (of hydrocarbon origins such as gasoline, naphtha, diesel, heavy oil, and crude oil) processing applications including biodiesel production. Herein, the role of cavitation reactors, their geometrical parameters, physicochemical properties of liquid media, liquid oxidants, catalyst loading, reactive oxygen species, and different types of emulsification and formation of radicals, formation as well as extraction of formed by-products are systematically reviewed. Among all types of HC reactors, vortex diode and single hole orifices revealed more than 95 % desulfurization yield and a 20 % viscosity reduction in heavy oil upgrading, while multi-hole orifice (100 holes) and slit Venturi allowed obtaining the best biodiesel production processes in terms of high (%) yield, low cost of treatment, and short processing time (5 min; 99 % biodiesel; 4.80 USD/m3). On the other hand, the acoustic cavitation devices are likely to be the most effective in biodiesel production based on ultrasonic bath (90 min; 95 %; 6.7 $/m3) and desulfurization treatment based on ultrasonic transducers (15 min; 98.3 % desulfurization; 10.8 $/m3). The implementation of HC-based processes reveals to be the most cost-effective method over acoustic cavitation-based devices. Finally, by reviewing the ongoing applications and development works, the limitations and challenges for further research are addressed emphasizing the cleaner production and guidelines for future scientists to assure obtaining comprehensive data useful for the research community. 相似文献